EASA SIB BEA-2016-01: Embraer EMB-505 Aeroplanes - Yaw Damper Fail Due to Unreliable or Unavailable GPS Signal

What to do

Operators of Embraer EMB-505 airplanes should monitor for any CAUTION CAS messages and follow the associated Quick Reference Handbook (QRH) procedures immediately. If AHRS 1 FAULT and AHRS 2 FAULT messages appear simultaneously, pilots must limit airspeed to a maximum of 240 KIAS or 0.63 Mach. No compliance deadline is specified, but the recommended procedures should be implemented immediately upon encountering the issue.

Summary

Boletim Especial de Aeronavegabilidade BEA Nº 2016-01 is a special airworthiness bulletin addressing a yaw damper failure issue in Embraer S.A model EMB-505 airplanes (Phenom 300) caused by unreliable or unavailable GPS signals. The bulletin informs operators about degraded AHRS performance during GPS signal loss, which can lead to multiple system fault warnings and unexpected aircraft behavior. This document provides information and recommendations but does not mandate an Airworthiness Directive under RBAC Nº 39.

What changed

This bulletin introduces awareness of a potential failure mode in the EMB-505's yaw damper system linked to GPS signal instability, particularly during cruise flight. It highlights the operational impact of simultaneous GPS signal loss on AHRS and related flight systems and recommends specific operational procedures to mitigate risks. No regulatory mandates or Airworthiness Directives are issued at this time.

Why it matters

Understanding this issue is critical for operators and maintenance teams to prevent unexpected flight control anomalies and multiple caution messages that could lead to emergency descents or airspace disruption. Awareness allows flight crews to respond promptly to system fault indications, maintaining safety and compliance. It also informs compliance teams about current non-mandatory guidance that may affect operational procedures.